Conventional internal combustion engines operate on all cylinders regardless of power requirements, relying upon transmission shifts and/or fuel supply to vary the torque provided in accordance with demand. During most normal driving cycles only a portion of available engine power is utilized, but the entire engine is used for that portion of power. The result is inherent inefficiency of operation, wasted energy, excessive fuel consumption and excessive pollutant emissions.
The present invention overcomes many of the disadvantages of the usual internal combustion engines. In accordance with one form of the present invention, a modular engine assembly is provided which incorporates a kinetic energy storing device, for example a "floating" flywheel, and a plurality of engines which selectively engage the flywheel via automatic clutches. Initially, the vehicle transmission is driven by a single, primary engine which also drives the flywheel. As additional power is required, as indicated by a torque sensor, or as demanded by an overriding foot pedal position, an auxiliary engine (one or more) is initially started by clutch coupling to the flywheel and thereafter aids the primary engine in driving the transmission.
Modular design enables the practical use of inexpensive, efficient, low polluting, small bore internal combustion engines (e.g. 30-150 cubic inches displacement). Synchronization of spark firing of the primary and auxiliary engines is readily accomplished by a commercially available mini-computer device. While the primary engine includes a starter and manual or automatic choke, the auxiliary engine is supplied, in one form hereof, with a fixed, idealized air/fuel ratio, such as stoichiometric or leaner. Heat transformed from the primary engine to the auxiliary engine maintains the auxiliary engine in a "ready" condition.
In one form of the present invention, a sealed housing is provided around the flywheel and vacuum therein is established by connection to the intake manifold of the primary engine. Additionally, the primary engine drives the alternator, air conditioner, and/or other pumps and the like, in the usual manner. A hydrostatic transmission may be utilized which provides smooth, full-range control of speed and torque. Fluid slip clutches, such as silicon fluid clutches, may also be utilized to provide full floating operation of the flywheel during braking and idling conditions.
The present modular-floating flywheel construction also enables the primary engine to stop, rather than be operating, during a temporary pause in vehicle travel, since the flywheel will act to start the primary engine as well as the auxiliary engine. The result is a further reduction in fuel consumption and air pollution.
The "floating" flywheel permits a smoothness of operation usually obtained only with rotary power engines, enables the storage of normally wasted energy and provides for rapid acceleration when required. The effective horsepower of the engine is thus effectively increased. The primary and auxiliary engines can be identical or can be different, and engines as small as 20 horsepower can be used in conjunction with a larger (50-75 horsepower) engine to effectively drive a full sized automobile. Each engine is complete within itself, having the standard balancing flywheel, common to reciprocating piston engines. Pollutant emissions are low as a result of the extremely low fuel consumption and ability to drive the auxiliary engine with a fixed air/fuel ratio. Accordingly, the present invention provides an advantageous solution to current critical problems of fuel shortage and air pollution.
In another form of the present invention, primary and auxiliary engines of the rotary type are selectively coupled and decoupled one to the other depending upon power requirements during a particular driving condition. The mechanism for coupling and decoupling the engines includes a clutch having a heavy flange and which flange is continuously driven by the primary engine. The flange stores kinetic energy under normal conditions during which additional power beyond that afforded by the primary engine alone is not required. When such additional power is required, the clutch is actuated to couple the auxiliary engine to the rotating flange and the primary engine. The stored kinetic energy is utilized to bring the auxiliary engine up to or turn it over to a predetermined speed.
As the auxiliary engine is brought up to such speed by transfer of the stored kinetic energy from the flange to the auxiliary engine, a vacuum pressure actuated switch turns on the ignition for the auxiliary engine. Subsequently and at a higher vacuum pressure, an electrically actuated control valve shifts to communicate vacuum pressure from the manifold of the auxiliary engine to a vacuum slave valve. The latter vacuum, when subjected to such vacuum pressure, opens the throttle valve in the carburetor of the auxiliary engine. Thus, a fuel-air mixture is provided the auxiliary engine only after it is brought up to speed and its ignition is on. This substantially reduces emissions and provides for a lean burn.
In shutting down the auxiliary engine, the sequence is reversed. That is, the clutch is deenergized and the auxiliary engine is disconnected from the drive train. The control valve also shifts causing the slave valve to close the throttle valve and prevent further delivery of the fuel-air mixture to the auxiliary engine. As the auxiliary engine winds down, the vacuum switch turns off the ignition. By turning the ignition off after delivery of the fuel-air mixture is stopped, emission of unburned fuel is prevented. This vacuum operated system may also be utilized with primary and auxiliary engines of the piston as well as rotary types.
While the previously described forms of the present invention locate the kinetic energy storing device between the auxiliary engine and primary engine, another form of the present invention locates the kinetic energy storing device between the primary engine and the transmission, i.e. on the side of the primary engine remote from the auxiliary engine. This provides a more compact modular engine assembly, affords additional room in the engine compartment, enables the auxiliary and primary engines to be located together, which is mechanically and operationally desirable, enables production of the two engines on a single frame or base, and permits the main engine bearings to be more closely balanced, all while retaining the advantageous features of the modular engine assembly hereof.
In operation, the kinetic energy storing device is clutched to the primary engine whereby it is continuously driven thereby. When additional power is required, the clutch between the auxiliary engine and primary engine is actuated to couple the auxiliary engine to the primary engine and the kinetic energy storing device. Thus, the stored kinetic energy brings the auxiliary engine up to speed. In this form, the ignition to the auxiliary engine is maintained in an on condition, Thus, when the vacuum pressure actuates a control valve which results in opening the throttle valve in the carburetor, the auxiliary engine is fired and drives the transmission through the primary engine and the kinetic energy storing device. In shutting down the auxiliary engine, this sequence is reversed.
A further feature of the present invention resides in the circulation of a cooling fluid from the primary engine to the auxiliary engine at all times. In this manner, the auxiliary engine serves as a heat sink which is sufficient throughout substantially 90% of the driving cycle to maintain the primary engine cool. Thus, the primary engine need not be loaded throughout the majority of its driving cycle by a fan and consequently improved efficiency and economy is obtained. For that small portion of the driving cycle requiring auxiliary cooling, a fan is provided which is driven by a fan motor under the control of a thermostatic switch. When the cooling fluid reaches a predetermined temperature, the thermostatic switch actuates the fan motor to drive the fan and cool the auxiliary engine and circulating cooling fluid therein. When the engine temperature is reduced below the predetermined temperature, the thermostatic switch cuts off the fan motor.
In a further embodiment of the present invention, air actuated clutches are disposed between the flywheel and both the primary and auxiliary engines. The exhaust side of the air actuated clutches communicates with the exhaust stream. Upon deceleration, the auxiliary engine is declutched from the primary engine and the kinetic energy storing device. As is well known, increased quantities of unburned hydrocarbons are exhausted during deceleration. By directing the exhaust air from the clutch at the same time deceleration occurs, the exhaust air assists to more completely burn the hydrocarbons in the exhaust system.
Accordingly, it is the primary object of the present invention to provide a novel and improved modular engine assembly.
It is another object of the present invention to provide a novel and improved compact modular engine assembly.
It is still another object of the present invention to provide a novel and improved modular engine assembly having improved cooling characteristics.
It is a further object of the present invention to provide a novel and improved modular engine assembly having improved operation of automotive accessories and air conditioners.
It is a further object of the present invention to provide a novel and improved modular engine assembly having improved burning of the hydrocarbons in the engine exhaust.
It is a related object of the present invention to provide a novel and improved engine assembly having stored kinetic energy engine startup assistance.
To achieve the foregoing objects and other advantages in accordance with purposes of the present invention as embodied and broadly described herein and in one aspect thereof, the modular engine assembly of this invention is adapted for driving connection with a transmission and comprises a primary engine, means for starting the primary engine, an auxiliary engine disposed in tandem with the primary engine, means adjacent the end of the primary engine remote from the auxiliary engine for connecting the primary engine to the transmission for driving the latter by the primary engine, means for selectively coupling and decoupling the auxiliary engine and the primary engine one to the other for driving the transmission selectively by the primary engine or both the primary engine and the auxiliary engine and means for starting the auxiliary engine including means for storing kinetic energy developed by the primary engine and applying the kinetic energy to the auxiliary engine to assist in starting the auxiliary engine, the kinetic energy storing means and applying means being located adjacent the end of the primary engine remote from the auxiliary engine.
In another aspect of the present invention, there is provided an engine assembly for connection with the transmission driven thereby including an engine, means for connecting the engine to the transmission for driving the latter by the engine, means for starting the engine including means for storing kinetic energy developed by the engine when started, the kinetic energy storing means being located between the engine and the transmission, means for selectively coupling and decoupling the engine and the kinetic energy storing means one to the other, and means for controlling the coupling and decoupling means whereby the engine may be decoupled and stopped during low energy requirements and coupled to the kinetic energy storing means to apply kinetic energy stored thereby to the engine and assist in starting the engine.